Method/Apparatus/Procedure: The multiple equilibrium technique with direct aqueous injection into a gas chromatograph was used to determine the dimensionless Henry's law constant. A known volume of liquid and gas was introduced into a syringe and allowed to equilibrate. The ratio of gas to liquid volume was maintained constant. While vapor samples were injected direct into a gas chromatograph, the liquid samples were pre-concentrated by liquid-liquid extraction before analysis. The experiments were carried out in duplicates.